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Project Progress

During the period covered by this report, I have initiated a search for planets around K-giants with the Hobby-Eberly telescope (HET). Collaborators in this research are Drs. M. Konacki (Caltech) and A. Niedzielski (Toru Centre for Astronomy, Poland). Searches for and studies of planets around post-main sequence stars are important for our understanding of the formation and evolution of planetary systems. They probe the very old planetary systems that could have undergone a significant dynamical evolution driven by changes in their parent stars over billions of years. Although the identification of planets around K-giants is seriously complicated by their intrinsic radial velocity (RV) variability, we conservatively estimate that new planets can be detected around no less than 10 of the ~300 stars included in our survey.

Our K-giant survey is part of the campaign to select astrometric reference stars for 24 target stars to be searched for Earth-mass planets by the Space Interferometry Mission (SIM). These targets comprise the northern part of the list to be observed by the EPIcS team (http://planetquest.jpl.nasa.gov/SIM). A ~1 μas precision of the survey calls for reference stars that will keep the astrometric noise below that level. They also have to be prevalent enough to be easily found within 1º of a target for narrow-angle astrometry. These conditions appear to be best satisfied by K-giants at distances ~1 kpc away.